Former US ambassador to NATO Kurt Volker argues that the West should not wait for a single mass atrocity before it intervenes in Syria, as it did in Bosnia. What is the magic number of deaths that will prompt the international community to act? We've already passed 9,000.

UN observers speak with Syrian citizens during their visit to the pro-Syrian regime neighborhoods in Homs province on Monday April 23. Op-ed contributor and former US ambassador to NATO Kurt Volker writes that military intervention "is a difficult and dangerous course, surpassed only by the difficult and dangerous course we are already traveling."

Washington — President Obama was on the right track this week when he announced a new effort to monitor global hot spots and prevent mass atrocities before they happen.

But what about daily atrocities unfolding now in Syria – where a UN-brokered cease-fire is growing weaker by the day and the world refrains from intervening to stop the violence?

In this case, a history lesson from the Bosnian War is worth remembering. On May 1-2, 1993, negotiators at a resort outside of Athens reached agreement on the “Vance-Owen peace plan” aimed at ending Bosnia’s civil war. The plan required Bosnian Serbs to stop shelling Sarajevo, where Bosnian Muslims were under a year-long siege. The catch: Western military force might be required to implement the cease-fire.

In 1993, US Secretary of State Warren Christopher began consultations with European allies to gauge their level of support for military force. But instead of assuring that the United States was prepared to lead the charge, he asked allies whether they were prepared to implement the plan, without committing the US either way. (“Leading from behind” is what one might call this today.)

Sensing the US was not prepared to lead implementation – President Clinton had won the election just six months earlier on the slogan, “It’s the economy, stupid” – allies demurred.

Within a week, the Bosnian Serb parliament rejected the plan, and shelling resumed. The war raged for two more years, with the Bosnian enclaves of Gorazde and Zepa falling to ethnic Serb forces, their majority Bosniak populations forcibly expelled.

Then, in July 1995 in Srebrenica, Bosnian Serbs murdered more 7,000 Bosniaks in one, systematic slaughter. It was at that point that the West finally acted. To his lasting credit, President Clinton then determined that the US would lead. NATO used air power to suppress Bosnian Serb attacks on Sarajevo, and within months had committed to military implementation of the Dayton peace accord, driven to conclusion by American über-diplomat Richard Holbrooke. By December 1995, some 60,000 NATO troops were en route to Bosnia to implement the peace plan, 20,000 of them American.

What was the difference between May 1993 and July 1995? In terms of Western implementation – nothing. We did in 1995 roughly what we would have done in 1993, had we acted. But in terms of human cost – tens of thousands of lives were lost.

And that is the key lesson. Eventually, the West was willing to act. But it took a “catalyst” of thousands of lives lost in a single massacre to convince us to do what we could have done years before. Would it not have been better to have acted sooner and saved thousands of lives?

As we look back over recent decades, there have been a surprising number of mass-murder conflicts. Bosnia, Kosovo, Saddam Hussein’s attacks on the Kurds in Iraq, and Libya, to name a few. In each case, outside powers intervened at some point to stop the killing. The results – while imperfect – nonetheless saved thousands of lives and laid the groundwork for future settlements.

And of all these recent conflicts, which is the one we regret the most? Rwanda, where some 800,000 people were killed and the West did nothing.

This is the perspective one must bring to the conflict now raging in Syria.

Nearly all the arguments against intervention in Syria have merit. It is difficult. The Syrian military is strong. Outside powers such as Iran and Russia are engaged. The local politics are complicated. What comes after intervention? Who are the people we would help? What if a revolution is hijacked?

Sound familiar? It should. These are the same arguments, with a few modifications, that were heard before the interventions in Libya, Kosovo, Kurdish-Iraq, and Bosnia. And after hearing all of them, and seeing the killing continue, we should ask ourselves, “and then what?”

Imagine that after the shelling of Homs, after the shelling of Damascus suburbs, after everything we have seen over the past year, some new slaughter takes place. Imagine 5,000 people killed in one fell swoop. Or 7,000. Or 9,000. It’s happened before. In 1982, Bashar al-Assad’s father sent the military to the city of Hama to put down an armed insurrection, killing at least 10,000 people.

What is the magic number that will finally prompt the international community to act in Syria?

The moral principles arguing for intervention are already known: The Syrian government is engaged in a systematic campaign of mass murder, seeking to kill anyone who dares oppose it, in order to re-establish firm control. The state of Syria has a monopoly of force – in the military, police, intelligence services, and secret police. The people are standing up with great valor – but little capacity – to oppose such tyranny. Over 9,000 people have been killed – though over a year’s time, not at once.

How to intervene? There’s no easy answer, but having no answer is even worse. On the political side, we have to assume that Russia will block any intervention resolution in the UN Security Council. And so the world would need to be prepared to act without one – just as in Kosovo in 1999.

On the mechanics, it would require suppressing Syria’s offensive capabilities and air defenses and jamming communications. A “safe zone” would need to be established inside the country, which would allow for unfettered distribution of humanitarian relief and create a space where the opposition could organize and receive further training and support (think Benghazi in Libya).

This is a difficult and dangerous course, surpassed only by the difficult and dangerous course we are already traveling.

What is missing, therefore, is not an understanding of the case for intervention, or even a means to intervene, but a “catalyst” that justifies and forces action. If that catalyst occurs, the US and others might act. And then America and its friends should ask themselves why they did not act sooner, and prevent the very catastrophe that spurred them into action.